Method of dyeing cellulosic substrates

Abstract

The present invention is related to methods for dyeing a traveling cellulosic substrate. The methods include steps of cationizing a cellulosic substrate followed by applying foam including one or more dyes to the cationized cellulosic substrate.

That which is claimed: 
     
       1. A method for dyeing a continuously traveling cellulosic substrate, consisting of:
 (a) cationizing a cellulosic substrate, wherein the cellulosic substrate comprises cotton, rayon, linen, or combinations thereof and includes a top surface and a bottom surface and wherein the cellulosic substrate is cationized by applying a liquid composition comprising 2,3-epoxypropyltrimethylammonium chloride; 
 (b) collecting the cellulosic substrate by a wrapping-and-rolling step performed by wrapping the substrate onto an uptake roll and rotating the substrate on the uptake roll from about 1 to 12 hours; 
 (c) applying a foam composition comprising a dye amount of one or more dyes comprised of fiber-reactive dyes, direct dyes, or combinations thereof, wherein the foam composition is applied in the absence of added sodium chloride or sodium sulfate salts via at least one applicator head in which each applicator head has a parabolic distribution chamber and a head slot that is disposed transversely with the continuously traveling substrate such that the foam composition is continuously applied to the traveling substrate through the applicator head, to provide a dyed substrate having between about 95 to 100% of the dye amount from the foam composition bound to the cellulosic substrate; and 
 (d) optionally:
 (i) generating the foam composition including one or more dyes, 
 (ii) washing the cellulosic substrate, 
 (iii) steaming the cellulosic substrate, 
 (iv) removing liquid from the cellulosic substrate, 
 (v) collecting the dyed substrate, 
 (vi) steaming the dyed substrate, 
 (vii) washing the dyed substrate, 
 (viii) removing liquid from the dyed substrate, 
 or combinations thereof. 
 
 
     
     
       2. The method of  claim 1 , wherein the foam composition is generated prior to applying the foam composition to at least one surface of the substrate. 
     
     
       3. The method of  claim 1 , wherein the head slot comprises a generally rectangular opening. 
     
     
       4. The method of  claim 1 , wherein a first applicator head is positioned underneath the traveling substrate such that the foam composition is continuously applied to the bottom surface of the substrate. 
     
     
       5. The method of  claim 4 , wherein a second applicator head is positioned above the traveling substrate such that the foam composition is continuously applied to the top surface of the substrate. 
     
     
       6. The method of  claim 4 , wherein the first applicator head is located upstream from the second applicator head. 
     
     
       7. The method of  claim 4 , wherein the first applicator head is located downstream from the second applicator head. 
     
     
       8. The method of  claim 4 , wherein the first and second applicator heads are positioned directly opposite one another. 
     
     
       9. The method of  claim 1 , wherein 2,3-epoxypropyltrimethylammonium chloride is formed by mixing 3-chloro-2-hydroxypropyltrimethylammonium chloride with a base. 
     
     
       10. The method of  claim 1 , wherein cationizing the cellulosic substrate is performed by saturating the cellulosic substrate with the liquid composition including 2,3-epoxypropyltrimethylammonium chloride. 
     
     
       11. The method of  claim 1 , wherein removing liquid from the cellulosic substrate is performed by squeezing at least a portion of the liquid composition out of the substrate. 
     
     
       12. The method of  claim 1 , wherein removing liquid from the cellulosic substrate is performed by drying liquid from the substrate prior to dyeing. 
     
     
       13. The method of  claim 1 , wherein the cellulosic substrate is provided in the form of a yarn. 
     
     
       14. The method of  claim 1 , wherein the dyed substrate is subjected to a steaming step after the application of the foam composition. 
     
     
       15. The method of  claim 14 , wherein the dyed substrate is subjected to a steaming step from about 1 minute to about 5 minutes. 
     
     
       16. The method of  claim 1 , wherein steaming the dyed substrate is performed by subjecting the substrate to about 1.3 pounds of steam per yard of a 16 ounce/linear yard fabric or less. 
     
     
       17. The method of  claim 1 , wherein the cellulosic substrate is washed after the wrapping-and-rolling step and prior to step (c). 
     
     
       18. The method of  claim 17 , wherein removing liquid from the cellulosic substrate is performed by drying after the washing step and prior to step (c). 
     
     
       19. The method of  claim 1 , wherein washing the dyed substrate is performed by washing the dyed substrate in a reduced manner to limit electricity usage and water usage. 
     
     
       20. A method for dyeing a continuously traveling cellulosic substrate, consisting of:
 (a) a pre-treatment step performed by cationizing a cellulosic substrate with a liquid composition, wherein the cellulosic substrate comprises cotton, rayon, linen, or combinations thereof and includes a top surface and a bottom surface; 
 (b) generating a foam composition including one or more dyes; 
 (c) collecting the cellulosic substrate by a wrapping-and-rolling step, the wrapping and rolling step performed by wrapping the substrate onto an uptake roll and rotating the substrate on the uptake roll from about 1 to 12 hours; 
 (d) a dyeing step performed by applying the foam composition to at least one surface of the continuously traveling substrate, the foam composition being applied to the at least one surface of the continuously traveling substrate via at least one applicator head comprising a parabolic distribution chamber and a head slot that is disposed transversely with the continuously traveling substrate such that the foam composition is continuously applied to the traveling substrate through the applicator head to provide a dyed substrate having between about 95 to 100% of the dye amount from the foam composition bound to the cellulosic substrate; and 
 (d) optionally:
 (i) washing the cellulosic substrate, 
 (ii) steaming the cellulosic substrate, 
 (iii) removing liquid from the cellulosic substrate, 
 (iv) collecting the dyed substrate, 
 (v) steaming the dyed substrate, 
 (vi) washing the dyed substrate, 
 (vii) removing liquid from the dyed substrate, or combinations thereof. 
 
 
     
     
       21. The method of  claim 20 , wherein washing the dyed substrate is performed by washing the dyed substrate in a reduced manner to limit electricity usage and water usage.